The rated working condition of cooling water required by water chillers is 30~35℃. High water temperature and poor heat dissipation will inevitably lead to high condensation pressure, which often occurs in high temperature seasons. The reasons for the high water temperature may be: cooling tower failure, such as the fan does not turn on or even reverse, the water distributor does not turn, indicating that the cooling water temperature is very high and rises rapidly; The temperature outside is high, the waterway is short, and the amount of water that can be circulated is small. In this case, the cooling water temperature is generally maintained at a high level, which can be solved by increasing the water storage tank.
2, cooling water flow is insufficient, can not meet the rated water flow:
The main performance is that the pressure difference between the inlet and outlet of the unit becomes smaller (compared with the pressure difference at the initial stage of system operation) and the temperature difference becomes larger. The reason of insufficient water flow is that the system lacks water or has air. The solution is to install an exhaust valve at the height of the pipeline for exhaust. The pipeline filter is blocked or too fine, and the water permeability is limited. Appropriate filters should be selected and the filter screen should be cleaned regularly; Pump selection is small and incompatible with the system.
3, condenser scaling or blockage:
Condensed water is generally tap water, which is easy to scale above 30℃. Moreover, because the cooling tower is open and directly exposed to the air, dust and foreign matter can easily enter the cooling water system, resulting in dirty blockage of the condenser, small heat exchange area and low efficiency, which also affects the water flow. Its performance is that the pressure difference between the inlet and outlet water of the unit and the temperature difference become larger, the temperature of the condenser is very high when touched by hand, and the copper tube of the condenser heats up. The unit shall be backwashed regularly, and chemical cleaning and descaling shall be carried out when necessary.
4. Too much refrigerant charge:
This situation usually occurs after maintenance, which is characterized by high suction and discharge pressure, high equilibrium pressure and large working current of the compressor. Under rated working conditions, air should be exhausted according to suction and discharge pressure, balance pressure and working current until it is normal.
5, refrigerant mixed with air, nitrogen and other non-condensable gases:
This kind of situation usually happens after maintenance, and the vacuum pumping is not complete. Only empty, re-vacuumize and refill the refrigerant.
6. False alarm caused by electrical fault:
Due to damp, poor contact or damage of high-voltage protection relay, the electronic board of the unit is damp or damaged, and communication failure causes false alarm. This kind of false fault is often caused by the fact that the high-voltage fault indicator lamp on the electronic board is not lit or slightly lit, the manual reset of the high-voltage protection relay is invalid, the compressor running current is normal, and the suction and exhaust pressure are normal.
7, evaporation pressure is too low:
It may be that the evaporation pressure of the water-cooled chiller is too low because of insufficient refrigerant. Common causes: insufficient cold water; Less cooling load; Throttle orifice plate failure (only make evaporation pressure low); The evaporator heat transfer tube deteriorates heat transfer due to scale pollution (only the evaporation pressure is too low); Insufficient refrigerant dosage (only evaporation pressure is too low).
8, oil pressure difference is too low:
If the compressor oil pressure is too low, the compressor will stop running. The common reasons are: the oil filter is blocked; Too much refrigerant is mixed in the lubricating oil.
9, the oil temperature is too high:
The high oil temperature of refrigeration compressor and long-term operation will reduce the quality of refrigeration oil and even carbonize it. Common reasons: the cooling capacity of the oil cooler is reduced; Because the filter screen of the coolant filter is blocked, the supply of coolant cooled by the oil cooler is insufficient.
10, main motor overload:
Unbalanced phase voltage of power supply; The voltage drop of power supply line is large;